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Microwave

Since I’m putting together a 10Ghz Transverter, the question of TX/RX Switching and sequencing comes to mind when gathering all the components for the build. For sequencing, I had a good look around at what was available from various sources on the web, but always came back to the Minikits product.

It seems to tick all the boxes as to what I needed it to do, so I ordered the kit from Mark. It turned up a quick 2 days after the funds cleared, and I wasted no time in constructing and testing it with the little Yaesu FT817 rig I use for microwave IF.

The Minikits EME166 kit is supplied with a beautifully made double sided, solder masked and silk screened PCB measuring 94 x 55 mm. It features 4 sequenced outputs, works on a supply voltage of between 8 to 15Vdc. It will handle up to 4 watts of RF from the IF radio between 28 and 500Mhz. It can be switched by RF sensing, or from a 12 volt or 0 volt signal via the IF radio’s coax centre conductor. It can also be manually switched if that is required. This kit comes with all the parts you need, besides the IF RF connectors, so you can make up your own mind as to how you’ll roll.

There is some surface mount soldering involved, but if you’re “messing about with Microwaves” your probably quite used to hunching over a magnifier lamp and soldering tiny components by now!

I have it down to a fine art these days, fluxing the area to be soldered with a flux pen, nice new, fine, clean tip and doing everything in a small plastic tray (Fererro Rocher plastic chocolate container lids work well!) that fits the board I’m soldering to. I empty the tiny components into the tray and pick them up with tweezers and solder them onto the board in the tray – this very much reduces the risk of losing the tiny flea sized components. There is nothing worse than trying to find an 805 sized component on the floor or in the shag pile carpet! ( …even worse when you have no spares)

Besides the few smd parts that are fitted to the underside of the board, there are 4 smd diodes fitted to the top of the board. The rest of the conventional leaded components go on easily. I built the kit in around 4 hours. I’d class this kit as “intermediate” level, you’ll need some SMD soldering gear and some experience to successfully build the kit. Don’t forget to check the values of the resistors with your multimeter, it’s easy to make a mistake!

One of the good things about this upgraded version, ( it’s an update of the very popular EME66 sequencer kit that has found its way into many a Transverter project worldwide over the years) is the single in line connector for all the sequenced outputs. This makes it much easier and neater to wire the board into your project. It’s also over voltage an reverse polarity protected.

I elected to fit SMA connectors to the board. The only thing I’d like to see different in the next version is the facility to mount the connectors vertically on the board, so it will be much easier to work with a vertically mounted sequencer.

My RX/TX change over Relay is 26 Volts, and the kit allows you to easily integrate different voltages to be switched by omitting the required link and soldering the supply to be switched at this point. Here you can see where I have the 26v supply (yellow wire) coming in to TX2 where the link for the 12v supply would normally be. It’s versatile, flexible and simple. It’s probably a good idea to change the corresponding led resistor to a more suitable value than the 1K0 supplied for 12 v.

The RX and TX IF levels are adjustable via the trim pots. Installing Link 5 will switch in a delay back to RX when using SSB to stop the relay chattering. I found the delay a bit long when using RF switching for my tastes. This could possibly be shortened by changing the associated cap value, if required.

Finally, here is a short video of the sequencer in operation. I’m using my FT817 that has been modified to put 12 Volts on the centre conductor of the front panel BNC connector when the PTT is enabled. The switching delay trim pot adjustment on the EME166 is about set mid-way.

Conclusion: The Minikits EME166 Transverter kit comes highly recommended. The design is very versatile, flexible and uses super quality parts through out. Delivery was prompt and Mark was very easy and pleasant to deal with.

There seems to be quite a bit of surplus microwave gear about on *THAT* auction site and these units out of Israel are very interesting to say the least.

Even though I have a fully functioning 10Ghz field day transverter setup, I decided to buy one of these units, looking to get another 10Ghz transverter happening with the intention of having a “loaner” system – one that can be loaned out to other hams keen to have a taste of microwaves, Therefore more stations and more activity on 10Ghz for field days!

The 10Ghz (3cm) band is an ideal band to introduce a newcomer to the wonderful world of microwaves. It’s a popular band, so there are more likely to be more stations active on a field day weekend. Most hams that gravitate towards microwaves tend to get 10Ghz up and running before all the other bands as the gear is relatively common and it’s fairly cheap to get up and running.

The Eyal Gal units are a complete RX system requiring just an IF radio, a local oscillator and an antenna to receive a signal.

For transmit, things are a little more complicated. These units are a just an amplifier at 10Ghz, so we need to add a transmit mixer and some filtering to complete a transceiver.

There doesn’t seem to be an awful lot of info about them, but Roger, G8CUB has some info on his webpage, including some updates on some of the variations that exist on these units

Miguel, EA4EOZ also has a nice little page about his adventures with a -22 variant of these devices.

This blog is the story of how my unit is going together and the parts I’m using to make it happen.

First impressions…

Here are some images of the unit as it arrived from the seller art-in-part.

These units look to be well made, and the case is milled aluminium, with an aluminium back cover that cover the control side of things. The RF side has been seam welded covers so if you want to get in there, good luck!

The RF connections are all female SMA. The control/power supply connectors are .1 inch pitch spacing. Luckily I save a fair bit of surplus electronics stuff, so had a connector on hand that plugged straight in for the power connections…

The first thing I have organised for the system is a local oscillator multiplier from Graham, VK3XDK. This unit conveniently has two outputs at the required frequency for both TX and RX LO inputs so it was an easy choice. Just give the multiplier a clean signal at 1656Mhz and the first stage multiplies to 4468 and the second stage doubles this to our LO frequency of 9936Mhz.

I’ll add more to the blog as I progress…

Well!!! It’s been 4 years, and after losing interest in Amateur Radio, I’m back!

Now that the propagation on 40 meters has deteriorated after the winter months, with weak, watery signals the norm rather than the exception, my radio activities have swung to my other love, Microwaves!

I’m keen on the world above above 70 cm, and have been active in a lot of the WIA field days over the last few years. I have equipment for 2.4, 3.4 and 10 Ghz. the 10 Ghz is a Kuhne G3 unit purchased from Germany when the exchange rate was favorable with the Euro. The other 2 bands I constructed from Minikits Kits, from Mark, VK5EME.
A typical field day sees me often heading over to Yorke’s Peninsular, to the west of Adelaide to work the other stations in the contest, either those out and about “Roving”or other portable/home stations. I usually have all bands from 2m to 10Ghz except 5.7 Ghz. The contest is a lot of fun, and it’s a great weekend away for me and all my gear!

I decided to rectify my lack of 5.7 Ghz and look what was out there, either kits or ready made. The short answer is not a lot…Kuhne do their lovely G3 for 5.7 with 250 mW output for a price and there is the cheaper VK3XDK kit option but with roughly only 10 mW output…so you need the added expense of an amp…either way was looking expensive by the time you add all the extras like a PLL unit for the LO and then putting it in a box and making it pretty…As I was on a budget I needed to come up with something cheaper.

A few eBay sellers from Israel ( why is this country the RF surplus capital of the world?) have been offloading a fair bit of surplus Eyal Microwave Industries (EMI) gear, in the form of TX RX modules for several Microwave frequencies of interest to radio amateurs. The 10 and 11 Ghz units have been popular and Roger, G8CUB has a webpage with information on getting those units going, as well as details of units for other bands…

My interest picked up when I saw that there were units available from several suppliers that are listed as being on a frequency of 6Ghz, very close to the 5.7 Ghz amateur allocation in the 6 cm band…The price was right, so I decided to grab one, even though the info link in the auction was dead and I couldn’t find any info on the internet about them. I figured for the price, it was worth the risk, and if I could get the thing to play then I would be saving a lot of money, as I found out through extensive searching that these units had an output of over 1watt (31dBm), perfect for a field day rig.

The unit as it arrived from ebay…

I wasted no time in removing the back off the unit to discover what I could. I was keen to at least get some idea of the pinouts of the interface control connector. Thankfully, it was clearly marked…

In the mean time, Derek VK5RX, kindly sent me a PDF of the specifications he had found after talking with him when he rolled up at my recent Spring Field Day site at Kline’s Point, over on Yorke’s Peninsular. We had been talking about the 10Ghz Eyal Gal units as well as this one, and he was able to find the very document I had been searching fruitlessly for and send it to me!

Power Connector sorted…

After the reading the specification PDF, I was a little dissapointed. It seems these units are might or might not work, as they are designed for 6.5Ghz to 7.15Ghz. I sent the specification PDF to Roger G8CUB, and he seemed to think the same thing, but it still would be worth persuing…

I’ll still be trying to get it going, might possibly work with a 433Mhz IF but I’ll probably have more luck with a 1296Mhz IF.

Meanwhile, I’m waiting for a little -5volt module to complete the power supply requirement to the unit…

MORE TO COME…

Update 27/11/2013

Often, when building up projects, the actual item itself is relatively painless and goes together quickly and without hassle…however, Ive found that building the actual transverter itself is the easy part, its putting it in a box and wiring it up!!!

I live by the motto “never throw anything out” to a certain degree…and for this project, I have magpied just about all the things I’ll need to put the finished transverter in a box

With this Eyal unit, the power/control connections are via a molex connector, a rather small 6 pin job that I wasnt going to solder to.

The matching plug was available online, but by the time I purchased a minimum of 10 and added pins, it was close to 25 bucks delivered. Sorry!

My “never throw anything out” mantra paid dividends! In my box of wire that I keep from old copier/printers that I rob at work before they go to the recycler I was able to quickly locate a loom with the correct plug on it with colour coded wires…problem solved!

I’m now waiting for a couple of bits to complete the power requirements for the unit, I’ll then be able to fire it up and see if it works…